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The third component reflects a motivational withdrawal syndrome (defined here as dependence) when access to the drug is prevented. Such hedonic dysregulation is hypothesized to extend into protracted abstinence to provide a residual negative emotional state that enhances the salience of cues eliciting drug seeking and relapse.ĭefinitions and conceptual framework for hedonic dysregulation in addictionĭrug addiction is a chronically relapsing disorder characterized by ( i) compulsion to seek and take the drug, ( ii) loss of control in limiting intake, and ( iii) emergence of a negative emotional state (e.g., dysphoria, anxiety, irritability). A combination of decreased reward system function and increased brain stress response system function is hypothesized to be responsible for hedonic homeostatic dysregulation that drives drug seeking behavior in dependence. CRF receptor antagonists block excessive drug intake produced by dependence. Chronic exposure or extended access to self-administration of all major drugs of abuse produces during abstinence increases in reward thresholds, increases in aversive anxiety-like responses, increases in extracellular levels of CRF in the central nucleus of the amygdala, and increases in drug self-administration. Specific neurochemical elements in these structures include not only decreases in reward neurotransmission, such as decreases in dopamine and opioid peptide function in the ventral striatum, but also recruitment of brain stress systems, such as corticotropin-releasing factor (CRF), in the extended amygdala. The negative emotional state that drives such negative reinforcement is hypothesized to derive from dysregulation of key neurochemical elements involved in reward and stress within basal forebrain structures, including the ventral striatum and extended amygdala. Excessive drug taking then results in part via the construct of negative reinforcement. One such mechanism is the emergence of a negative emotional state when access to the drug is prevented, reflecting hedonic homeostatic dysregulation. Drug addiction can be defined by a compulsion to seek and take drug and loss of control in limiting intake, and the excessive drug taking derives from multiple motivational mechanisms.